Declension table of ?siddhānna

Neuter	Singular	Dual	Plural
Nominative	siddhānnam	siddhānne	siddhānnāni
Vocative	siddhānna	siddhānne	siddhānnāni
Accusative	siddhānnam	siddhānne	siddhānnāni
Instrumental	siddhānnena	siddhānnābhyām	siddhānnaiḥ
Dative	siddhānnāya	siddhānnābhyām	siddhānnebhyaḥ
Ablative	siddhānnāt	siddhānnābhyām	siddhānnebhyaḥ
Genitive	siddhānnasya	siddhānnayoḥ	siddhānnānām
Locative	siddhānne	siddhānnayoḥ	siddhānneṣu

Compound siddhānna -

Adverb -siddhānnam -siddhānnāt